Practical strategies for modulating foam cell formation and behavior.

Although high density lipoprotein (HDL)-mediated reverse cholesterol transport is crucial to the prevention and reversal of atheroma, a recent meta-analysis makes evident that current pharmaceutical strategies for modulating HDL cholesterol levels lower cardiovascular risk only to the extent that they concurrently decrease low density lipoprotein (LDL) cholesterol. This corresponds well with findings of a recent Mendelian randomization analysis, in which genetic polymorphisms associated with HDL cholesterol but no other known cardiovascular risk factors failed to predict risk for myocardial infarction. Although it is still seems appropriate to search for therapies that could improve the efficiency with which HDL particles induce reverse cholesterol transport, targeting HDL cholesterol levels per se with current measures appears to be futile. It may therefore be more promising to promote reverse cholesterol transport with agents that directly target foam cells. Macrophage expression of the cholesterol transport proteins adenosine triphosphate binding cassette transporter A1, adenosine triphosphate binding cassette transporter G1, and scavenger receptor class B member 1 is transcriptionally up-regulated by activated liver X receptors (LXR), whereas nuclear factor (NF)-kappaB antagonizes their expression. Taurine, which inhibits atherogenesis in rodent studies, has just been discovered to act as a weak agonist for LXRalpha. Conversely, it may be possible to oppose NF-kappaB activation in macrophages with a range of measures. Induction of heme oxygenase-1, which can be attained with phase 2 inducer phytochemicals such as lipoic acid and green tea catechins, promotes reverse cholesterol transport in macrophages and inhibits atherogenesis in rodents, likely due to, in large part, NF-kappaB antagonism. Inhibition of macrophage nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity with the spirulina-derived bilirubin-mimetic phycocyanobilin may also oppose NF-kappaB activation, and salicylic acid similarly should be useful for this purpose. The 5' adenosine monophosphate-activated protein kinase activator berberine promotes macrophage reverse cholesterol transport in cell culture; metformin probably shares this property. Many of these measures could also be expected to promote plaque stability by suppressing foam cell production of inflammatory cytokines and matrix metalloproteinases, and to reduce intimal monocyte infiltration by anti-inflammatory effects on vascular endothelium. Direct targeting of foam cells with agents such as phase 2 inducers, spirulina, salicylate, taurine, and berberine or metformin, may hence have considerable potential for preventing and reversing atheroma, and for preventing the plaque rupture that triggers vascular thrombosis.

Animal models of atherosclerosis.

In this mini-review several commonly used animal models of atherosclerosis have been discussed. Among them, emphasis has been made on mice, rabbits, pigs and non-human primates. Although these animal models have played a significant role in our understanding of induction of atherosclerotic lesions, we still lack a reliable animal model for regression of the disease. Researchers have reported several genetically modified and transgenic animal models that replicate human atherosclerosis, however each of current animal models have some limitations. Among these animal models, the apolipoprotein (apo) E-knockout (KO) mice have been used extensively because they develop spontaneous atherosclerosis. Furthermore, atherosclerotic lesions developed in this model depending on experimental design may resemble humans' stable and unstable atherosclerotic lesions. This mouse model of hypercholesterolemia and atherosclerosis has been also used to investigate the impact of oxidative stress and inflammation on atherogenesis. Low density lipoprotein (LDL)-r-KO mice are a model of human familial hypercholesterolemia. However, unlike apo E-KO mice, the LDL-r-KO mice do not develop spontaneous atherosclerosis. Both apo E-KO and LDL-r-KO mice have been employed to generate other relevant mouse models of cardiovascular disease through breeding strategies. In addition to mice, rabbits have been used extensively particularly to understand the mechanisms of cholesterol-induced atherosclerosis. The present review paper details the characteristics of animal models that are used in atherosclerosis research.

Hypothesis: smoking decreases breast feeding duration by suppressing prolactin secretion.

A number of studies, including new data summarized here, conclude that breast feeding duration is lower in smoking mothers. Although some have suggested that this merely reflects poor health motivation in those prone to smoke, several lines of evidence support the view that chronic smoking does indeed compromise breast feeding by suppressing prolactin secretion and thereby lowering breast milk volume. Moreover, a recent clinical trial shows that an effective smoking cessation program can boost breast feeding duration in smokers. An analysis of pertinent rodents studies suggests that chronic nicotine administration boosts dopaminergic activity in the tuberoinfundibular tract which functions to inhibit prolactin release; this increase in dopaminergic activity, in turn, may reflect a nicotine-mediated suppression of hypothalamic opioid activity.

Polymorphisms of the hypoxia-inducible factor 1 gene and peripheral artery disease.

Hypoxia-inducible factor 1 (HIF1) is a key regulator of angiogenesis and is involved in inflammation, which are two important features of the pathogenesis of peripheral artery disease (PAD). The gene for the HIF1-alpha subunit (HIF1A) carries two common mis-sense mutations, P582S (C>T, rs11549465) and A588T (G>A, rs11549467), which both have been related to increased trans-activation capacity of HIF1-alpha. The aim of the present study was to analyze the role of these polymorphisms in PAD. The study was designed as a case-control study including 917 patients with documented PAD and 969 control subjects. HIF1A genotypes were determined by exonuclease (TaqMan) assays. HIF1A P582S genotype frequencies were not significantly different between PAD patients (PP 82.2%; PS 16.5%; SS 1.3%) and control subjects (83.2%; 15.3%; 1.5%; p = 0.72). Similarly, HIF1A A588T genotype frequencies did not differ significantly between PAD patients (AA 95.9%; AT 4.1%) and control subjects (AA 96.8%; AT 3.2%; p = 0.28). In a multivariate logistic regression analysis including age, sex, smoking, diabetes, arterial hypertension and hypercholesterolemia, neither the HIF1A P582S polymorphism (odds ratio: 1.26; 95% confidence interval 0.92-1.74; p = 0.16) nor the A588T polymorphism (odds ratio: 1.17; 95% confidence interval 0.59-2.35; p = 0.66) was significantly associated with the presence of PAD. Both polymorphisms were furthermore not associated with age at onset of PAD, Fontaine stage of the disease or the ankle/brachial index of patients. We conclude that functional polymorphisms in the HIF1A gene do not contribute to susceptibility to PAD.

The fibrinogen gamma 10034C>T polymorphism is not associated with Peripheral Arterial Disease.

Conversion of fibrinogen to fibrin plays an essential role in hemostasis and results in stabilization of the fibrin clot. Fibrinogen consists of three pairs of non-identical polypeptide chains, encoded by different genes (fibrinogen alpha [FGA], fibrinogen beta [FGB] and fibrinogen gamma [FGG]). A functional single nucleotide polymorphism (SNP) in the 3' untranslated region of the FGG gene (FGG 10034C>T, rs2066865) has been associated with deep venous thrombosis and myocardial infarction. Aim of the present study was to analyze the role of this polymorphism in peripheral arterial disease (PAD). The study was designed as case-control study including 891 patients with documented PAD and 777 control subjects. FGG genotypes were determined by exonuclease (TaqMan) assays. FGG genotype frequencies were not significantly different between PAD patients (CC: 57.3%, CT: 36.7%, TT: 5.8%) and control subjects (CC: 60.9%, CT: 33.5%, TT 5.6%; p=0.35). In a multivariate logistic regression analysis including age, sex, smoking, diabetes, arterial hypertension and hypercholesterolemia, the FGG 10034 T variant was not significantly associated with the presence of PAD (Odds ratio 1.07, 95% confidence interval 0.84 - 1.37; p = 0.60). The FGG 10034C>T polymorphism was furthermore not associated with age at onset of PAD. We conclude that the thrombophilic FGG 10034 T gene variant does not contribute to the genetic susceptibility to PAD.

omega-3 Fatty acids infusions as adjuvant therapy in rheumatoid arthritis.

BACKGROUND: The present study investigated the efficacy and safety of parenteral omega-3 fatty acids (omega-3 FA) in patients with active rheumatoid arthritis (RA). METHODS: We performed a double-blind, randomized, placebo-controlled study in 23 patients with moderate to severe RA. Patients received either 0.2 g of fish oil emulsion/kg (active) or 0.9% saline (placebo) infusion intravenously for 14 consecutive days, followed by 20 weeks of 0.05 g of fish oil/kg (active) or paraffin wax (placebo) ingested orally as capsules. A decrease in swollen and tender joint counts was the primary efficacy measure. RESULTS: At baseline, both swollen and tender joint counts were not significantly different between patients in the treatment and placebo groups. Twenty patients completed the infusion portion of the study, and 13 completed the oral portion. Swollen joint count was significantly lower in the omega-3 FA group compared with the placebo group after 1 week of infusion (P = .002) as well as after 2 weeks of infusion (P = .046). Tender joint count also tended to be lower in the omega-3 FA group, although this did not reach statistical significance. Both swollen and tender joint counts were significantly lower in the omega-3 FA group compared with the placebo group during and at the end of oral treatment. CONCLUSION: Our pilot study indicates that parenteral omega-3 FAs are well tolerated and improve clinical symptoms of RA. Subsequent oral administration of omega-3 FAs may prolong the beneficial effects of the infusion therapy. These results warrant validation in larger multicenter studies.